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Hugh MacIsaac – 2003

May 13, 2003 @ 2:30 pm – 4:00 pm
Senate Chamber, N940, Ross Building, York University

Title: Predicting biological invasions in the great lakes and inland lakes in Ontario.

Abstract: Invasions by non-indigenous species (NIS) are the second leading threat to global biodiversity and the leading threat to lakes. Work in our lab addresses invasion vectors that bring NIS to the Great Lakes, and from the Great Lakes to inland lakes; we utilize a number of approaches including modelling, genetic analyses, tracking of shipping traffic and ballast water discharge patterns.

One area of particular interest to us is how dispersal of invertebrate species can be effected by ‘resting’ eggs, propagules which evolved to tolerate adverse environmental conditions but which now serve to allow human-mediated transfer of species to new lakes. Many NIS are native to the Black Sea region of eastern Europe, invade major port areas in the North and Baltic Seas, and arrive to the Great Lakes in a wave of secondary invasions from these locations. The invertebrate waterfleas Bythotrephes and Cercopagis, for example, invaded the Great Lakes from the Baltic Sea. These species alter food webs and impart economic damage. Ballast water discharge patterns indicate that Lake Superior should be the most vulnerable Great Lake to invasions, yet the most invaded ‘hotspot’ is the southern Lake Huron – western Lake Erie corridor.

Invasion of the Great Lakes often portends invasion of inland lakes. For example, the invertebrate waterflea Bythotrephes has spread to ~ 55 inland lakes throughout Ontario, particularly in the Muskoka region. We developed a vector-based model to assess spread of this species via human dispersal mechanisms (e.g. contaminated fishing line) that transport it from invaded source to noninvaded destination lakes. This model successfully hindcasts and forecasts invasions based simply on vector flows. The network of ‘outflow’ connections from invaded lakes to other invaded lakes as well as to noninvaded lakes has increased exponentially over the past decade as more systems became invaded.

Curtailing spread of NIS globally will require a comprehensive, collaborative effort to identify and eliminate invasion pathways that bring nonindigenous species to our forests and agricultural and aquatic ecosystems. Managerial efforts on the Great Lakes must focus on primary (e.g. shipping) and secondary (e.g. bait fish, aquaculture, live fish sales) dispersal vectors, while those on inland lakes will require concerted public education campaigns. Efforts to prevent invasion of lakes that could function as ‘hubs’ for future invasions is an imperative. Brochure - Y-File Article

Updated on August 7th, 2014.